1. Field of the Invention
This invention relates to a hose for a vacuum, especially a retractable hose.
2. Description of the Related Art
A number of patents and published patent applications apply to retractable hoses for vacuum systems.
U.S. Pat. No. 5,740,581 applies to a vacuum hose where a horizontal partition is placed between two wall studs. The upper end of the hose has a handle. Below the handle the hose passes through a drive assembly for pulling the hose below the handle into the space below the partition and then extending the hose when desired.
In the device of U.S. Pat. No. 6,182,327, a handle of a hose is maintained on one side of a conduit through which the remainder of the hose passes into a basket. As the hose drops into the basket, the forces created thereby cause the basket to rotate and coil the hose.
The vacuum hose of U.S. Pat. No. 5,526,842 is retracted onto a spring-loaded reel, which may be located within a wall. A hinged door is urged by a spring toward a closed position. When it is open, the door bears against corrugations of the hose to prevent the hose from being retracted into the wall; it is not used to facilitate the retention of the hose within the wall or other container.
International publication no. WO 01/24677 describes a hose which fits inside and has a head end extending from an open end of a conduit that also has a terminal end. An annular seal is attached to the foot end of the hose to minimize the flow of air past the hose. A cover is “hingedley” attached to the head end of the hose and is, preferably, spring biased to urge the cover closed when a handle is not attached. Then, when a vacuum is applied to the terminal end of the conduit, external air pressure pushes the hose into the conduit. An annular flange acts as a stop against a wall receptacle to preclude the entire hose from being pushed into the conduit. The length of the hose does, however, not vary.
The hose of European patent application no. 1 176 352 has a wall composed of a helical spring covered by two layers of material through which air does not pass. Such layers are bonded to one another around the spring but not in between windings of the spring, thereby creating a continuous helically channel between the windings of the spring. The spring is biased to retract. A pump pushes air into the channel when it is closed in order to extend the hose and withdraws such air to facilitate retraction of the hose.
Appearing most closely related to the present invention, though, is one embodiment of the device described in United States patent application publication no. US 2003/0098084.
The embodiment of interest is a vacuum hose which has a helical spring inside the wall of the hose. Between coils of the spring the wall bows inward. The spring “. . . is biased to expand the hose . . . to its fully extended length. This means that in its compressed position . . . , spring 36b is under compression forces, with force needed to keep it in this retracted state (the force may come from either vacuum pressure and/or support housing). In its relaxed state, the hose . . . can be fully extended and bias spring 36b can still be exerting an extension force on the hose . . . .”
The free end of the hose incorporates a rather complex wand, the complexity of which suggests that a simple valve would be inadequate to retract the hose.
Both a wall-mounted version of the vacuum hose and a portable version are discussed.
The wall-mounted version holds the body of the compressed hose inside a tube with the wand being “snapped (or locked, or clipped, etc.) into place in wand indentation 262” so that the hose can be held in a retracted position without the vacuum operating. And “a door . . . may be place[d] on holding case 260 to provide a clean finish look for the wall in which this hose system is installed. This door can also help hold hose wand 28 in place while not in use.”
In the portable version the hose has “a locking end . . . on one end, and hose wand housing . . . on the other.” The hose is locked to a vacuum source either with a tube around the hose extending from the wand or a tube inside the hose extending from the wand. The fact that the tube has a locking end at its end which is opposite to the end with the wand, therefore, unfortunately creates a rather lengthy (exceeding the length of the compressed hose) inflexible section of hose that is attached to the wand even when the hose is extended.
Finally, in U.S. Pat. No. 5,114,050 two embodiments of an elevated vacuum hose are shown. In a first embodiment the vacuum hose is held on a reel. In the second embodiment a short flexible hose hangs “in the form of an inverted U” and is retained in an elevated position by a spring so that it can be grasped and pulled to an operating position. The length of the hoses of this patent does not, however, vary, i.e., the length of the hoses cannot be extended or retracted.